biostudies-literatureUnknown31(10)Oortveld MAWDeficiency of the cysteine protease inhibitor cystatin M/E (Cst6) in mice leads to disturbed epidermal cornification, impaired barrier function, and neonatal lethality. We report the rescue of the lethal skin phenotype of <i>ichq</i> (Cst6-deficient; <i>Cst6</i>^-/-) mice by transgenic, epidermis-specific, reexpression of Cst6 under control of the human involucrin (INV) promoter. Rescued Tg(INV-<i>Cst6</i>)<i>Cst6^ichq/ichq</i> mice survive the neonatal phase, but display severe eye pathology and alopecia after 4 mo. We observed keratitis and squamous metaplasia of the corneal epithelium, comparable to <i>Cst6^-/-Ctsl^+/-</i> mice, as we have reported in other studies. We found the INV promoter to be active in the hair follicle infundibulum; however,FASEB journal : official publication of the Federation of American Societies for Experimental Biology4286-4294https://www.ebi.ac.uk/biostudies/studies/S-EPMC5602906biostudies-literatureCathepsin B as a potential cystatin M/E target in the mouse hair follicle.PMC5602906Cheng TOortveld MAWVerdoes MReinheckel TSchalkwijk Jvan Erp PEJHendriks WJAJZeeuwen PLJMKersten FFJVerbeek Svan Vlijmen-Willems IMJJfalseCathepsin B as a potential cystatin M/E target in the mouse hair follicle.Deficiency of the cysteine protease inhibitor cystatin M/E (Cst6) in mice leads to disturbed epidermal cornification, impaired barrier function, and neonatal lethality. We report the rescue of the lethal skin phenotype of <i>ichq</i> (Cst6-deficient; <i>Cst6</i>^-/-) mice by transgenic, epidermis-specific, reexpression of Cst6 under control of the human involucrin (INV) promoter. Rescued Tg(INV-<i>Cst6</i>)<i>Cst6^ichq/ichq</i> mice survive the neonatal phase, but display severe eye pathology and alopecia after 4 mo. We observed keratitis and squamous metaplasia of the corneal epithelium, comparable to <i>Cst6^-/-Ctsl^+/-</i> mice, as we have reported in other studies. We found the INV promoter to be active in the hair follicle infundibulum; however,2017-01-01T00:00:00Z2017 Oct2025-04-05T14:31:21.925Z2019-03-27T02:56:39ZS-EPMC56029062859623410.1096/fj.201700267R